Process for manufacture of chlorhydrines



DecI. 14,. 1937. n E-ROY U. SPENCE v` 2,102,042

PROCESS FOR MANUFACTURE OF C HLORHYDRINES Filed Jan.. 23,- 1936 `2'Sheets-Sheet 1 egj/ Z6. Spence,

Dec. 14,v 1937.. LEROY u. sPENc'E 2,102,042

PROCESS FOR MANUFACTURE OF GHLORHYDRINES Filed Jan. 25, 1956 2Sheets-Sheet 2 julien ZeJEqy 5l; Spence,

Patented Dec. 14, 1937 `UNITI-:o STATES PROCESS FOR MANUFACTURE OFCHLOE- HYDRINES Le Roy Spence, Cheltenham, Pa., assignor to Rhm & HaasCompany, Philadelphia, Pa.

Application January '23, 1936, serial No. 60,445 11 claimsxv (ci.26o-15"!) This invention relates to a process and apparatus forintimately associating a liquid solution with a finely dispersedinsoluble or diflicultly soluble gas for chemical reaction therewith.

process and apparatus for the production of alkylene chlorhydrines fromgaseous unsaturated hydrocarbons and chlorine in aqueous solution.

In chemical processes in which an 'insoluble gas is reacted with acomponent'of `a solution, it is essential that a large surface contactarea Y be maintained between the gaseous phase and the liquid phase ifthe reaction is to proceed with any degree of rapidity. Heretofore, thecustomary method of obtaining the necessary d egree of surface contactwas to cause the liquid and gas to flow countercurrent in a suitablechamber over and through a packing-having a large surfacetarea.l Anothermethod was to vigorously agitate the liquid and gas in a .large reactionvessel equipped with a powerful stirrer.

In the preparation of alkylene chlorhydrines by the reaction ofhypochlorous acid and gaseous olefines, the common practice heretoforehas been to prepare the hypochlorous acid `either by the action ofchlorine on aqueous solutions of alkalies or alkali carbonates, orsuspensions of lime at low temperatures, or by dissolving chlorine inwater. The use of alkalies and low temperatures is objectionable becauseof the increased cost incident to their use. The practical utilizationof chlorine water involves considerable diiiiculties due to the presenceof free chlorine that reacts with `the clef-lne to form the alkylenedichloride. `f

The present invention has for its primary object the provision ofamethod and apparatus for the economical use of gaseous olef'lne,chlorine and water -inthe production of alkylene 40 chlorhydrines. Afurther object is the develop- V.ment of a process and apparatus for theeconomical production of alkylene chlorhydrines wherein the productionof ,almrlene dichlorides is reduced to a minimum. Another object of theinvention is the development'of a system for the continuous orintermittent production of alkylene chlorhydrines which provides forrecirculating the aqueous liquor and .unreacted gases. A still furtherobject is to vproduce. an apparatus for 'intimately associating a gasand a liquid whereby a large surface contact areal will4 be maintainedbetween the Vtwo phases. These. and other objects will become apparentirom the following description.

More particularly, the invention relates to a.

In the present invention these objects are at-` tained by introducinginto the upper portion of a vertical reaction zone gaseousl oleiines andchlorine in parallel ow with a circulating aqueous liquid and ladjustingthe flow of the liquid to carry the gas slowly down through the reactionzone. This may be accomplished. by means of an aspirator or liquid jetpump or by forcing the gases under pressure directly into a rapidlymoving stream of the circulating liquid. When an aspirator is used, itis preferably-located at the upper end .of a vertical tower with Ydispersion thus insuring intimate contact with the-liquid. The aspiratormay be omitted and the chlorine and olefine forced directly into therapidly moving stream of the circulating liquid before it entersdownwardly into the reaction tower. Due to the high velocity of theliquid the gases will be dispersed in the form of very ne bubbles beforeentering the tower. Furthermore, by flowing the liquid downward throughthe tower and adjusting its rate of flow, the tendency of the bubbles torise and collect can be overcome and thus a larger quantity of liquidwill come in contact with the highly dispersed gases. The rate at which.the liquid passes through the tower is adjusted so that the bubblesmove slowly down the tower and, if not absorbed, are carried out at thebottom thereof. 3

For a more complete description .of the invention, reference will bemade to the accompanying drawings in which like numerals indicatesimilar parts. In the drawings Fig. l is a verticalsectlon of apreferred form of Vthe apparatus in which chlorine and gaseous olene areinjected ytogether into the reaction chamber. Fig. 2 is a verticalsection of a similar apparatus in which'a separate tower is provided fordissolving chlorine in the circulating liquid before it enters thereaction chamber. Fig. 3 is a cross section of the preferred form ofaspirator used.

Referring to the drawings, the numeral (i) indicates a cylindrical'reaction chamber or tower having at its upper end a downwardly pointed,

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separates from the reaction liquor in a gas separator (1). A coolingcoil (8) is provided to remove the heat generated by the reaction. Awater inlet valve (9) may be provided in pipe line (I0) for initiallylling the apparatus with water and when the apparatus is operated as acontinuous process, for supplying additional water to the system. Afluid pump (I I) maintains a continuous circulation ofl fluid throughthe pipe line (I2) to the aspirator (I3), thence into and through thereaction tower (I), the draw-oit line (I4), the gas separator (1)., thecooling coil (8) and back through pipe fine (I0) to the low pressureside of the pump. A drawoff valve (I5) is provided to remove liquid fromthe system when it has become sufficiently concentrated with alkylenechlorhydrine. A gas vent (24) having a control valve (25) is provided tovent the gas separator when necessary. The gas separator should also beprovided with a pressure gauge (26) and liquid level gauge (21) fordetermining the gas pressure and liquid level within the separator.

In the apparatus as illustrated in Fig. 2 an absorption ,tower (I6) isprovided for dissolving chlorine in the circulating liquid before it isintroduced into the reaction chamber (I).

Such absorption tower may be conveniently located as a by-pass in pipeline (I2) whereby a portion of the circulating liquid is withdrawn fromthe pipe (I2) through a valve (I1) and aspirator (I8) into and throughthe absorption tower (I6) and thence through -the pipe line (I9) and,when valve (2|) is closed, through pipe (20) and valve (22) into theupper portion of the reaction tower (I). A valve (23) is provided insection (IZA) of pipe line (I2) to cooperate with valve (Il) to'adjustthe relative proportion of circulating liquid that passes through theabsorption tower (I6) to that Winch passes directly through theaspirator (I 3) Alternatively, by closing valves (22) and (23) andopening` valves (I1) and (2`I) all the circulating .liquid can be passedthrough the absorption tower (I6) pipe' line (I9) valve (2|) section(I2B) of pipe line (I2) and thence through the aspirator (I3) into thereaction chamber (I). The aspirator (I8) is of. a construction similarto that of aspirator (I3) and is provided with a gas inlet valve (3) fordrawing chlorine into the absorption tower.

The apparatus `shown in Fig. 1 is preferred for the manufacture ofethylene chlorhydrine and can be used for the manufacture of thechlorhydrines of the higher olefines. .Howeven the higher oleilnes reactmore readily with gaseous chlorine than does ethylene and .their mixturewith chlorine should be avoided as much as possible. For the production1of chlorhydrines of the higher oleflnes, the apparatus of the type shownin Fig. 2 is preferred in -whlch the chlorine is allowed to react withthe water to form hypochlorous acid before'coming into contact with theoleiine.

In the production of ethylene chlorhydrine in the apparatus shown inFig. 1 the operation is started by first lling the system with waterthrough valve (9), air vent (24) being opened for this purpose. Whilethe apparatus is being illled pump (II) is operated to insure thecomplete removal of air from all parts of the apparatus. After the airis removed, valve (9) is closed and valves (2) and-(I5) opened, wherebyethylene is drawn in and replacesY a portion of the water withdrawnthrough valve (I5). The

'and (3) pumping rate is adjusted so that the bubbles of ethylene formedby the aspirator (I3) move slowly down the reaction tower (I) and intothe gas separator (1). After the ethylene begins to collect in the gasseparator, valves (2) are opened to admit equimolecular amounts ofethylene and chlorine, and valve (5) opened to permit the recirculationo1' the ethylene collected in they gas separator. The water passingthrough the aspirator (I3) at high velocity draws in the ethylene andchlorine, disperses them in the reaction tower in a very ne state ofsubdivision and vigorously agitates the `liquid in the upper portionthereof. The liquid as it travels down the tower in opposition to thetendency. of the bubbles to rise, carries the gas in its highlydispersed state down with it, whereby the tower becomes substantiallyfilled with small bubbles. A condition is thereby produced which isideal for the solution of chlorine in water and the reaction betweenethylene and the hypochlorous acid formed. The ethylene chlorhydrinethus produced, being soluble `in water, circulates with water throughthe apparatus until its concentration reaches about 6% by weight,whereupon the solution is removed from the system through'- valve (I5)and replaced with fresh water through valve (9).

While the use of an aspirator to draw the gaseous materials into thesystem is preferred it is not essential and may be replaced by suitablepumps that positively force the gaseous materials into the circulatingliquid.

The temperature should be maintained at about 40v C. during theoperation and it is desirable to have a slight excess of ethylene in thesystem. The pumping rate necessary to keep the bubbles from rising inthe reaction tower is approximately 30 to 35 cubic feet per minute persquare foot cross section of the reaction tower. Operating in this way ayield of ethylene chlorhydrine 94% of the theoretical can be obtained.This amounts to a 47% conversion of chlorine to ethylene chlorhydrine,47% conversion to hydrochloric acid and 6% conversion to oils consistingchieily of ethylene dichloride with some dichlorethylether. It isapparent that by the continuous addition of water through valve (9) `andthe removal of an equal amount of solution from valve (I5) the operationmay be carried on continuously. If desired however, the apparatus may beoperated as a batch process by the complete removal of liquid whentheconcentration of ethylene chlorhydrine reaches approximately 6%; Whenoperating as a continuous process, the addition of Water should beadjusted so that the product removed throug'h valve (I5) will containapproximately 6% ethylene chlorhydrine by weight.

The apparatus as illustrated in Fig. 2 is operated in much the same wayas has been described for Fig. 1, except that a portion or all of thecirculating liquid is passed through an absorption tower (I6) in whichit absorbs chlorine andv from there passes to the reaction tower (I).The action of the aspirators (I3) and (I8) in commingling the liquid andgas and agitating the two phases in the absorption and reaction tower isthe same as that previously described for Fig. 1. A system of thisnature is particularly suited for the production of ethylenechlorhydrine and the higher alkylene chlorhydrines.

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In both types of apparatus the maximum yields of the chlorhydrine areobtained when solutions containing 4 to 6% by weight of chlorhydine areare removed' from the system.I However, solutions Aof a concentration ashighas 15 and 16% chlorhydrine may be prepared', but the yields will beslightly lower than whenl a 6% solution is' removed. The yieldsobtainedrby a batch pro ess are also slightly better than those obtainedwhen the apparatus is operated continuously. For instance, an 8%solution of ethylene chlorhydrine `Waspreparecl by a batch operationwith a yield of 91 to 92% of the theoretical, while a continuous processunder the same conditions gave an 89 to 90% yield; The process may beoperated over a considerable range of temperature (10 C. to 80 C.) buttherange of 30-50" C.

is preferred, and the best yields lobtained at, about 40.

'I'he pumping'rate necessary to disperse the bubbles ina 4-6% solutionof chlorhydrine at temperatures of 30-40" C. wasfound to beapproximately 30-35 cubic feet per minute per square foot of tower crosssection.A If a solution stronger than 6% or hotter than 40 C. is used,

a higher pumping rate may be required to keep the gases highly dispersed,and moving slowlydown the tower.

The size of the gas separator must besuch that the velocity of theliquid in it is low enough 4to permit the bubbles-of gas to rise andseparate V rine and may be periodically removed through the vent line(24). If a mixture of gases, such as the mixed hydrocarbons and oleilnesobtained in the cracking of petroleum, is used, the recirculation of thegases from the separator may be omitted, since the amount of inert gasesin such mixtures is high.

It has been found that this process and apparatus can be used for thepreparation' of chlorhydrines of all the common unsaturated gaseousoleflnes, such as ethylene, propylene, butene-l, butene-2 isobutylene,etc. or mixtures of these.

The chlorhydrines may be separated from the solution withdrawn bysalting, distillation, extraction-or other known means, or the Solutionmay be used as it is obtained to.prepare glycols or alkylene oxides.

This invention furnishes a practical and simple `4 described thepreferred apparatus and mode of` operation, it would be obvious to oneskilled in the art that modifications may be made therein withoutdeparting from vthe scope thereof. It is also apparent that theapparatus described may be suitably modified and usein any chemicalreaction between a liquidor solutionand a relatively insoluble gas. Itis to be understood that all mattei' contained in the above descriptionis illustrative and that the invention is limited through a secondreaction chamber at a rate only by the scope of the followingfclaims.

-I claim:

.1. Inl the manufacture of alkylene chlorhydrine vfrom gaseous 4oleiine,chlorine and water the steps of producing a large surface contactbetween liquid and gas by aspirating the chlorine and gaseous oleilneintol a body of water by means of a flowing stream of water, and flowingsaid body of water downwardly through a reaction chamber at a rateslightly in excess of that necessary to overcome the tendency of the gasbubbles to rise.

. 2. In the manufacture of alkylene chlorhydrine steps of aspirating thegaseous oleilne and chlorine into a bocLv of water by means of a owingstream of water, flowing said body of water downwardly through areaction chamber at a rate slightly in excess of that necessary toovercome the tendency of the bubbles to rise, and thereafter separatingthe unreacted gases from the aqueous liquor.

3. In the manufacture of alkylene chlorhydrine from gaseous olene,chlorine and water the from gaseous oleilne, chlorine and water the A.steps of aspirating the gaseous oleflne and chlorine into a body ofwater byv means of a flowing stream of water, flowing said body of waterdownwardly through a reaction chamber at a rate slightly in excess ofthat necessary to overcome the tendency of thebubbles to rise, andrecirculating the aqueous liquor until the alkylene chlorhydrine contentthereof reaches a con-l centration of between 1 and 16%.

4. In the manufacture of ethylene chlorhydrine from ethylene, chlorineand water the steps of producing a large surface contact between liquidand gas by aspirating a mixture of ethylene and chlorine into a body ofwater by means of a flowing stream of water. and flowing said body ofwater downwardly through a reaction cham-.- ber at arate slightly inexcess of that necessary to overcome the tendency of the gas bubbles torise.

5. In the manufacture of ethylene chlorhydrine from ethylene, chlorineand water the steps of aspirating a mixture of ethylene and chlorineinto Aa body of water by means of a owing ,stream of water, flowingsaidv body of Water downwardly through a reaction chamber at' a rateVslightly in excess of that necessary'v to overcome the tendency of thebubbles to rise, and thereafter separating the unreacted gases from theaqueous liquor.

6. In the manufacture of ethylene chlorhydrine from ethylene, chlorineand water the -steps of aspirating a mixture of ethylene and chlorineintoa body of water by means of a flowing stream of water, owing saidbody of water downwardly through a reaction chamber at av rate slightlyin excess of that necessary to overcome the tendency of the bubbles ,torisa-and recirculating the aqueous liquor until the' ethylenechlorhydrine content thereof reaches a con to overcome the tendency ofthe chlorine bubbles l to rise, flowingthe solution thus formed througha second aspirator to aspirate olefine into said solution and owing thesolution downwardly slightly in excess of that required to' overcome thetendency of the olene bubbles to rise.

8. In the manufacture of alkylene chlorhydrine from gaseous oleflne.chlorine and water" the steps of aspirating the gaseous olene andchlorine into a body of water by means of a flowing stream of water,flowing said body of water downwardly through a reaction chamber at arate slightly in excess of that necessary to overcome the tendency ofthe bubbles to rise, recirculating the aqueous liquor until the alkylenechlorhydrine content thereof reaches a concentration of between l and16% and continuously removing said solution from and adding anapproximately equal volume of water to the circulating liquid.

9.` In the manufacture of alkylene chlorhydrlne from gaseous olene,chlorine and water the steps of introducing said. gases into a rapidlymoving stream of water and passing the water and gas in a downwarddirection through a reaction zone at such rate that the bubbles of thegas move slowly downwards.

10. Inthe manufacture of ethylene chlorhydrine from ethylene, chlorineand water thev steps of introducing the ethylene and chlorine into arapidly moving stream of water and passing the water and gas` in adownward direction through a reaction zone at such rate that ythebubbles of the gas move slowly downwards.

11. In the manufacture of ethylene chlorhydrine from ethylene, chlorineand water the steps of aspirating chlorine into a body of water by meansof a flowing stream of water, flowing the water downwardly through areaction chamber at a rate slightly in excess of that required toovercome the tendency of the chlorine bubbles to rise, flowing thesolution thus formed through a second aspirator to aspirate the ethyleneinto said solution and flowing the solution downwardly through a secondreaction chamber at a rate slightly in excess of that required toovercome the tendency of the ethylene bubbles to rise.

LE ROY U. SPENCE.

